Emerald Iron Sentinel

dark fantasy illustration, towering shield guardian construct, broad-shouldered and looming in a protective stance with one arm raised to conjure a shimmering force barrier, crumbling stone hall of an ancient wizard’s tower with shattered runes glowing underfoot, dramatic backlighting from a blown-out doorway casting long shadows and metallic rim light along engraved plates, atmosphere thick with dust motes and drifting embers, mood of unstoppable vigilance and implacable power, palette of cold steel blues and muted brass with sharp accents of emerald arcane light, ultra-detailed digital painting with engraved armor textures, hairline cracks, and glowing sigil in its chest core